Technical data

Chapter 2 File 8
2. File
The file menu contains a number of commands for opening and closing image files, printing images and selecting and
maintaining the various databases used by Autostar Suite.
Open
The Open command allows you open either images or spectrographs in any of the following formats.
TIFF - Tagged Image File Format (8 or 16 bit grayscale)
FITS - Flexible Information Transport System (8, 16 bit bit grayscale)
BMP - Windows Bitmap Format (8 bit grayscale/256 color)
LNX - Spectra Source Lynxx format (12 bit grayscale)
ST6 - Santa Barbara Instrument Group (16 bit grayscale)
ST4 - Santa Barbara Instrument Group (8 bit grayscale)
08B - Raw (8 bit grayscale). Similar to ST4.
Images may only be saved in TIFF, FITS or BMP formats.
To open a file:
- Select the desired format.
- Select the directory and filename from the list boxes
OR
- Enter the desired filename in the Edit box.
If the filename is specified without an extension, a default extension will be automatically added to the filename to
reflect the current format. If the extension is provided, it will over-ride the current selection
The file will be loaded into two separate memory buffers, namely the display buffer and buffer A. The display buffer
contains the image that is currently displayed on the screen, while buffer A is used as the source for the image
processing functions. When an image processing function begins it copies the current display buffer into buffer A.
If the image file is part of an RGB composite image (red, green or blue), you may choose which RGB buffer to use as
the destination. If you have selected either the Red, Green or Blue buffer, the buffer will be created, and the image will
be copied into the buffer automatically. You may also copy the current image into the RGB buffers at a later time by
using the Copy Image command.
8 Bit versus.12 or 16 Bit Images
When 12 or 16 bit images are loaded, they must first be compressed down to 8 bits (256 gray levels), which is the
maximum number of simultaneous colors that Windows can display at one time. To prevent the loss of important data,
Autostar Suite automatically senses the larger data format and displays the Image Prescale dialog box, which allows
either automatic or manual setting of the parameters used to compress the data into an 8 bit format. This dialog box
displays the histogram of the 16 bit data in a large graph at the top and, at the bottom, a smaller graph of the resulting
data after compression.